1. Field of the Invention
The present invention relates to a field of radiographic digital image processing, and more particularly, to a multiple view angle X-ray stereoscopic imaging method and system thereof.
2. Description of the Related Art
X-ray imaging technology has been widely applied to various fields of industrial nondestructive testing, medical diagnosis, and scientific research. Three dimensional or stereoscopic display technology is used to enhance the spatial position information for radiography, and to enable examiners to understand better the spatial relations between defects or foreign matters. By capture a series of scanning images at different angles, Computerized Tomography (CT) calculates tomography images of an object using a tomography reconstruction algorithm, and renders a three dimensional image through a three dimensional visualization method. Although CT can obtain precise three dimensional spatial information, calculation amount of both reconstruction calculation and three dimensional rendering is very large and needs relatively long computation time such that it is difficult for CT to meet with the requirement for real-time application. Moreover, the price of whole system is also very expensive.
Since the stereoscopic X-ray imaging technology was presented in the initial stage of the twentieth century, most of the stereoscopic X-ray imaging systems have been designed by using the parallax principle. The principle of such a stereoscopic X-ray imaging system is described as follows. Two X-ray images corresponding to the left and right eyes are obtained by using various methods. Then the left eye sees only the image corresponding to the left eye and the right eye sees only the other image corresponding to the right eye using various display modes. Finally, the images corresponding to the left and right eyes are combined into a stereoscopic image by human brain. Stereoscopic images can enhance the spatial position information for images and improve the observation effects of the spatial structure relation of a examined object. A method most usually used for obtaining an X-ray stereogram is to shift the X-ray source or move an imaging screen between two exposures. Another method is to catch two images at different angles as an X-ray stereogram by rotating the X-ray source and imaging screen or rotating the object by a small angle. Although the methods for capture X-ray stereograms are different, all of them have such a defect that they only provide a stereoscopic image at the shooting angle, but the position of viewpoint, the direction of sight line, and the parallax are all fixed. Thus, these methods could not meet the parallax requirement for the human's observation. To obtain a stereoscopic image at other angles, shooting must be implemented again at another position.